The bitter Senate fight to confirm Brett M. Kavanaugh to the Supreme Court plunged into deeper chaos Thursday as a top Democrat disclosed she had referred “information” about President Trump’s nominee to the FBI.

Sen. Dianne Feinstein (D-Calif.) issued a brief, cryptic statement about the referral, but the absence of any details only raised questions. The information came in a letter that describes an alleged episode of sexual misconduct involving the 53-year-old Kavanaugh when he was in high school, according to a person familiar with the matter.

The White House decried the move as a desperate, last-minute campaign to tear down a qualified nominee, and the FBI does not plan on investigating the matter, which erupted publicly as Democrats complained that Kavanaugh is unfit for the high court.

The abrupt disclosure came as an intensely political battle over Kavanaugh’s confirmation continued to escalate, with a handful of moderate senators who would decide his fate deliberating on how they would vote on a nominee who could shift the balance of the court to the right for generations.

Top Senate Republicans said Kavanaugh’s nomination remains on track, but two swing GOP votes — Sen. Susan Collins of Maine and Lisa Murkowski of Alaska — have not announced their positions and face intense pressure at home to oppose Kavanaugh, injecting uncertainty into the outcome. Collins said she had lingering questions and plans to speak to Kavanaugh on Friday. In Alaska, the state’s largest Native American organization urged Murkowski to reject the nominee.

Democrats have thrown increasingly charged questions at Kavanaugh as they face a furious liberal base pushing senators to do everything within their power to sink his nomination — sometimes without offering public evidence of their claims.

Sen. Sheldon Whitehouse (D-R.I.) asked Kavanaugh several questions in writing about gambling, including whether the judge had ever reported a gambling loss to the Internal Revenue Service and whether Kavanaugh had sought treatment for a gambling addiction. The nominee said no to both questions.

“All of our questions were predicated on documents produced to the committee, information relayed by law enforcement, or media investigations on the subject of which we became aware,” Whitehouse said.

But the drama on Thursday centered on the mysterious letter.

Democrats on the committee first learned about the letter’s contents at a meeting called at the last minute on Wednesday night. The letter had been relayed to Feinstein, the top Democrat on the Judiciary Committee, by Rep. Anna G. Eshoo (D-Calif.), two people familiar with the matter said.

“That individual strongly requested confidentiality, declined to come forward or press the matter further, and I have honored that decision,” Feinstein said in a statement. “I have, however, referred the matter to federal investigative authorities.”

Emma Crisci, a spokeswoman for Eshoo, said she could not comment because of a confidentiality policy involving constituent casework.

Other Democratic senators on the committee — who have, for weeks, been furious with the GOP over how they’ve proceeded with Kavanaugh’s nomination — declined to comment on the letter’s contents and the uncertainty that it caused. But privately, some Democrats had asked Feinstein about the letter’s substance as chatter about its existence emerged within the last week or so, prompting the last-minute meeting just off the Senate chamber.

The White House immediately pushed back on the development as a “smear” attempt to derail Kavanaugh’s confirmation, which Senate Republicans plan to complete before Oct. 1, the first day of the court’s fall term. The Senate Judiciary Committee decided Thursday to vote on the nomination Sept. 20.

“Throughout his confirmation process, Judge Kavanaugh has had 65 meetings with senators — including with Senator Feinstein — sat through over 30 hours of testimony, addressed over 2,000 questions in a public setting and additional questions in a confidential session,” White House spokeswoman Kerri Kupec said. “Not until the eve of his confirmation has Sen. Feinstein or anyone raised the specter of new ‘information’ about him.”

Kupec noted that the FBI has “thoroughly and repeatedly vetted” Kavanaugh through his 25-year public-service career, which includes work in the Office of Independent Counsel under Kenneth Starr, the George W. Bush White House, and his current position on the D.C. Circuit Court of Appeals.

The spokeswoman also accused Senate Minority Leader Charles E. Schumer (D-N.Y.) of masterminding the latest developments surrounding the letter. But a Schumer aide said the senator has not had access to the letter.

The White House did not return a request for comment specifically on the sexual misconduct allegation.

Several officials confirmed that the letter was referred to the FBI. But the bureau does not plan to launch a criminal investigation, according to a person familiar with the matter — a probe that would normally be handled by local authorities if it were within the statute of limitations.

Instead, the FBI passed the material to the White House as an update to Kavanaugh's background check, which already has been completed, the person said. The move is similar to what the bureau did when allegations were leveled against former White House aide Rob Porter, who resigned earlier this year after the emergence of domestic abuse accusations from two former wives.

Once the White House received the material from the FBI, which it did early Thursday afternoon, it sent the information to the Senate Judiciary Committee, according to an administration official.

“Upon receipt of the information on the night of Sept. 12, we included it as part of Judge Kavanaugh’s background file, as per the standard process,” an FBI spokesperson said. The Justice Department declined to comment.

The allegation of sexual misconduct in the letter was first reported by the New York Times. The existence of the letter was first reported by the news website the Intercept. Senate Judiciary Committee Chairman Charles E. Grassley (R-Iowa) said Thursday morning that he had not seen the letter, so he could not comment on its contents.

The controversy arose in the final stages of Kavanaugh’s confirmation fight, as Democrats have sought to delay the process.

Senate Majority Leader Mitch McConnell (R-Ky.) is intent on setting up votes in the full Senate for the last week of September. Feinstein’s disclosure did nothing to change the timeline, as a spokesman for Grassley confirmed that the committee vote would proceed as scheduled.

In a chamber where Republicans hold a 51-to-49 majority, Kavanaugh will be confirmed as long as he loses no more than one GOP vote. While Collins and Murkowski haven’t announced their decisions, they have shown no signs publicly that they are struggling to get to a “yes” on his confirmation.

When asked whether she wanted to see the letter that began the swirl of controversy on Thursday, Collins declined to respond, saying she would not make any more public comments until she was ready to announce her position.

But her office has faced a firestorm of calls from Kavanaugh opponents, with the protests sometimes coming in a profane and vulgar manner that has been denounced by Republican senators and some Democrats. On Thursday, a three-foot-long cardboard cutout of male genitalia, accompanied by a profanity, was sent to Collins’s Washington office, according to her staff.

Collins had already been the target of a crowdfunding campaign that topped $1 million from anti-Kavanaugh activists, who pledged to donate that money to a Collins challenger during her reelection bid in 2020 if she voted to confirm him. A spokeswoman for Collins called it an attempt at extortion.

Meanwhile, in a clear attempt to influence Murkowski, the influential Alaska Federation of Natives said Kavanaugh’s legal views on Indian rights are “troubling” and would be bad for “for Native peoples, particularly Alaska Natives and Native Hawaiians.”

As she walked into the Judiciary Committee offices Thursday, Murkowski said she had no update on her thinking on Kavanaugh.

Among Democrats, three moderate senators who are seen as the most likely to vote in favor of Kavanaugh had also yet to make up their minds. Sens. Joe Manchin III (W.Va.), Joe Donnelly (Ind.) and Heidi Heitkamp (N.D.) continued to deliberate Thursday, and Manchin was seeking a second sit-down meeting with Kavanaugh.

Some other Democrats — including Sen. Patrick J. Leahy (D-Vt.) — announced their opposition to Kavanaugh on Thursday. Leahy also said he supported how Feinstein had handled the disclosure of the sensitive information. “She’s not a person to try to smear anybody,” Leahy said. “She’s always done her job, she’s always done it with integrity.”

“Let me get this straight: this is [a] statement about [a] secret letter regarding a secret matter and an unidentified person. Right,” he tweeted sarcastically. “I will add: the FBI already performed and has reported on a background investigation on the nominee and this has been made available to all Senators on the Judiciary Committee.”

Matt Zapotosky, Robert Barnes and Amy Brittain contributed to this report.

Seung Min KimSeung Min Kim is a White House reporter for The Washington Post, covering the Trump administration through the lens of Capitol Hill. Before joining The Washington Post in 2018, she spent more than eight years at Politico, primarily covering the Senate and immigration policy. Follow

Elise ViebeckElise Viebeck is a political enterprise and investigations reporter. She joined The Washington Post in 2015. Follow